Bucky grid actuating device



Feb. 14, 1939. E? s. FLARSHEIM 2,147,601

' BUCKY GRID ACTUATING DEVICE I Filed Nov. so, 1936 3 sheets-sheet 1zzgl.

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Feb. 14, 1939,

E. S. FLARSHEIM BUCKY GRID ACTUATING DEVICE Filed Nov. so, i936 5sheets-sheet 2 INVENTOR ATTORNEYS Feb. 14, 1939. E s FLARsHElM y2,147,601

BUCKY GRID ACTUATING DEVICE Filed NovQ 50', 193e 3 sheets-snee@ 3INVENTOR.

*ZI-Qui? BY k n ATTORNEYJ Patented Feb. 14, 1939 i UNITED STATES PATENTOFFICE.

BUCKY GRID ACTUATING DEVICE Application November 3 0, 1936, Serial No.113,357

11 Claims.

This invention relates to X-ray apparatus, and particularly to mechanismfor regulating the speed of travel of bucky grids which are'conventionally interposed between the subject matter being X-rayed andthe sensitized plate to screen out secondary radiation. The grid ismoved above and across the sensitized plate while the picture is beingtaken, and the opaque strips, usually lead strips, accomplish thespecified screening function. l

It is desirable that a predetermined motion be imparted to the buckygrid in its travel across the sensitized plate. One type of bucky gridactuating device, in which mechanism is employed for determining andcontrolling the speed of travel of the bucky grid, is found in PatentNumber 1,945,499, issued t me January 30, 1934. ',Ihis invention findsready application to the apparatus of the patent mentioned above. Itsconcern is with the question of speed and the problems resulting from itin the split second operation and control of a high speed bucky grid.

With the advent of higher speed X-ray apparatus, wherein the picture istaken at an increasingly greater speed, it follows that the grid must beoperable at a speed commensurate therewith. Absolute and sensitivecontrol is necessary to achieve perfect timing. Moreover, due to thefact vthat the grid moves across a relatively short space at high speedand must be stopped within this space, the problem'of `concussion andjar occurring at the stops is presented. This heavy jar `Sets upvibration having a damaging effect on the picture, and in additiondisplaces and damages the mechanism.

It is therefore the object of this invention to provide a bucky gridoperating apparatus for high speed usage which is accurately controlledand timed for split second operation, which does not permit slamming ofthe grid into the stops, but prevents shock or concussion by acushioning action at the end of grid movement, which is effectivedespite the extreme velocity of the grid and which apparatus, therefore,solves all the problems of high speed bucky grid operation.

Other objects and further advantages will be more fully apparent from adescription of the accompanying drawings, in which:

Figure l is a fragmentary top plan view of the bucky grid assemblyshowing the improved mechanism.

Figure 2 is an enlarged sectional view taken on line 2 2, Figure 1.

Figure 3 is a fragmentary enlarged sectional view showing the partsspread out and illustrating the control means for the operatingmechanisms of the bucky grid.

Figure 3A is an enlarged sectional view of the piston shown in Figure 3.Figure 4 is a fragmentary partly sectional view of a portion of thebucky grid shown in Figure 1, but showing the grid in the last phase ofits movement during the taking of a picture.

Figure 5 is a fragmentary sectional view taken similarly to Figure 3illustrating the control -10 means in detail in its position when thebucky grid is slightly beyond the position shown in Figure 4, movementhaving just terminated.

Figure 6 is a sectional View taken on line 6 6, Figure 5, detailing thecontrol valve incorporated l5 in the oil circuit controlling themovement of the bucky grid.

Figure 7 is a sectional view taken on line 1 7, Figure 5, illustratingthe time setting means for positioning the valve for determining thespeed at which the bucky grid travels across the sensitized plate.

Figure 8 is a fragmentary View taken similarly to Figure 1, but showinga modied form of the invention. 25

Figure 9 is an enlarged fragmentary view of a portion of Figure 8,showing the control or decelerating means operated for slowing down thebucky grid in the nal phase of its movement.

Figure l0 is a sectional view taken on line IIJ- 30 I0, Figure 9,detailing the auxiliary or decelerating valve.

Figure 11 is a sectional view taken on line I I-f Il, Figure 8, showingthe decelerating valve in opened position.

Figure 12 is a sectional View taken similarly to Figure l1, but showingthe valve in position for decelerating bucky grid movement.

' The bucky grid I0 is not shown relative to the X-ray lamp, and itsdetailed arrangement rela- 40 tive to the sensitized plate and table arenot fully illustrated, since this mechanism is well understood in theart and is conventional. For the -purposes of this invention, the buckygrid I0 is shown slidably mounted in a frame Il, for movement above andacross the sensitized plate l2, lying therebeneath,

Referring specifically to the drawings, the bucky grid l0 includes lugsi3, two one each side thereof. These lugs on one side are slidablymounted on respective rods I4 carried by brackets l5 of the frame Il. Onthe other side, the lugs are slidably mounted on the side wall of theframe.

As illustrated in Figure 1, the bucky grid Il) is manually set on itsmounting for subsequent operation or automatically controlled return, bymeans of a lever I6 fulcrumed on the frame as at I1, and having one endengaging a lug I3 of the bucky grid. A pull rod I8, guided through theframe II has one end attached to the end of the lever opposite the buckygrid engaging end, and its outer end provided with a knob I9. A spring2U, disposed under tension between the lever and the frame toward theactuating end of the lever, returns the setting means (lever I6, rod I8,and knob I9) to its normal or original position automatically after thebucky grid Vactuating mechanism has been cocked.

A coil spring 2I is disposed under tension between the frame II and anextension 22 of the lug I3, thus exerting a constant return force on thebucky grid. The bucky grid is held against the action of the returnspring by means of a latch or hook element 23, which drops into theposition over a co-operating hook element 24 of the frame. The latch istripped by means of a trigger element 25, pivoted on the frame and swunginto engagement with the latch by means of a pull rod 28, extending tothe forward end of the bucky grid frame. The pull rod, or wire, providesan operating ring 21, and is spring returned to its normal or initialposition by means of a coil spring 28 under tension and connectedbetween a cross member of the frame and the pull rod.

The frame II includes a cross rail IIa at the end containing the controlmechanism, the cross rail defining the chamber containing thismechanism. The brackets I5 which slidably support the bucky grid aremounted on this cross rail I Ia.

An arm 29 extends from a bearing bracket I3, and is rigidly connectedwith the outer end of a piston rod 33. A cylinder 3l, including cylinderheads 32 and 33, is attached to the wall Ia of the frame by means ofscrews 34-34 extending through the cylinder heads into the wall I Ia. ofthe frame. The piston rod 30 extends through the cylinder head 32 andhas screw threads on its outer end upon which is a pair of nuts 35,which adjustably secure the rod to the arm 29 so that the position ofthe piston 3S may be adjusted relative to the bucky grid. As stated, aspring 2l is provided for moving the bucky grid above and across thesensitized plate while the picture is being taken. This spring 2l isdisposed parallel with the piston rod and exerts a direct pull action.on the bucky grid through the arm connection The piston rod, it will benoted, extends through one end of the cylinder and is of extremely smalldiameter or small cross section. This light rod is possible due to thefact that the return force, as imparted by the spring 2l, is a pullforce and there is no tendency to buckle the rod or destroy itsalignment. Moreover, it is easy to pack this light rod in the cylinderhead for there is less area or leakage surface. For the purpose of thispacking, a plurality of washers 31, preferably of leather, is disposedsnugly about the rod within a concentric recess 33, in the cylinder head32. A nut 39 is screwed onto a boss 40 and urges a spring 4I undercompression against these washers 31 tending to press and expand themwithin the recess 38 and against the piston rod.

For the purpose of the by-passage of the fluid `used in the cylinder,preferably oil, the cylinder heads 32 and 33 are extended laterally (seeFigure 3) and each extension includes a passageway 42. A pipe 43 isattached between the lateral extensions and connects the passageways42-42. Since the passageways 42-42 are in connection with the cylinder,this pipe establishes a circuitous path or by-passage for the iiuid. Thecylinder 3l, heads 32-33, and pipe 43, are held in assembly, with thecylinder and pipe maintained in socketed position in the heads by meansof the attachment of the heads to the frame. A filter screen 44 isinterposed in the fluid passage between the head 33 and the cylinder 3l.

Two valves are inserted in the uid passageway. One is a fluiddisplacement control valve 45, and s included in the piston 3S, forautomatically opening a passage through the piston to permit idle ilowof oil therethrough when the piston is being set or cocked by settingthe bucky grid. The other of these valves is a manually or automaticallyoperated bypass control valve 46, mounted in the extension of thecylinder head 32 in the iluid passageway 42. This latter valve functionsfor permitting and controlling the effective bucky grid movements,governing the passage of. oil as the spring 2| acts to return the pistonand the bucky grid.

The valve 45 in the piston 36 is illustrated in detail in Figure 3A. Inthis View it is closed, assuming that the piston is starting its path oftravel under the influence of the spring 2|. The valve element 45 isrigidly attached or carried on the inner end of the piston rod andconstitutes the connection of the piston rod to the piston. The pistonincludes a bore having a shouldered internal flange 41 includedintermediate the bore length. The Valve element 45 has a head 48 havinga serrated or grooved periphery for uid passage. The head 43 of thevalve element is slidably mounted in the end of the bore opposite to theextent of the piston rod and a sleeve portion 49 of the valve element isextended loosely through the piston, clearing the bore in the internalflange 41.

A sleeve element or spring retainer 50 is malntained on the end of thesleeve at the end opposite its head by means of a nut 5I on the valveelement. This sleeve element or spring retainer 50 includes a headengaged against a compression spring seated against the internal iange41 of the piston. The head of the spring retainer clears the piston boreand longitudinal slots 52 in the opposite end thereof entering anenlarged bore portion 53 of the spring retainer 50 to open the fluidpassage through the piston when the valve is open or unseated.

Therefore, when setting of the bucky grid occurs, it moves the pistonrod, and the piston rod is not effective for moving the piston until thevalve element has been moved within the piston and unseated, and thespring retainer has engaged the piston. Thereafter, the piston may bemoved to a set position due to the relief of fluid therethrough,although the manual control bypass valve 46 may be closed at the time.

The valve 46 is of rotatable type and is adjusted by rotation eithermanually or automatically in accordance with the invention as hereafterdescribed. The valve includes a valve body mounted in the passageway 42in an enlarged chamber thereof. The valve body is tubular and is closedat its outer end, its bore being aligned with the portion of thepassageway 42 extending to the pipe 43. The passageway 42 enters thevalve chamber at right angles thereto. A circumferentially taperedgroove 55 is formed in the valve body adjacent to the passageway 42 anda radial aperture 56 connects the groove to the bore of thevalve body(see Figure 6). The valve stem is sealed in the cylinder head at thepoint where it extends to the exterior by means of a packing identicalto that used for the piston the spring and as permitted by theby-passage of iluid through the valve 46, will occur.

In order to permit displacement of oil such as Occurs because oftemperature change and because of the entrance of the piston rod intothe cylinder, a metal bellows 58 is provided. This bellows is attachedto the cylinder head 33 and communicates with the passageway 42 and,therefore, the fluid system by means of a nipple 59.

For the bellows, a plurality of annular folds 60 is formed of sheetmetal and a head 6l is provided at each end. A bracket 62 supports theouter end of the bellows by means of the slidable engagement of a stud63 extendedV axially from the head through the bracket. Expansion andcontraction of the bellows is permitted by the slidable support.

Therefore, the fluid system is flexible despite its sealed conditionsand the problems arising from the use of a piston rod extending onlyfrom one end of the cylinder, and the expansion and contraction of theoil as occasioned by the temperature change are taken care of.

Thefollowing apparatus is provided for manual and automatic setting ofthe valve 46. The valve stem 64 extends substantially to the end wallofthe frame II. The rod is sectional and is provided with a universaljoint to allow a certain amount of flexibility in order to preventbinding at the valve and to permit expansion and contraction. For thispurpose the adjacent ends of the section carry coupling elements 65-85(see Figures 2 and 3) secured to the respective sections by means ofscrews 66. A spring plate disc B1 is interposed between the couplingelement 65-65 and has its margin secured to these coupling elements.Each element is secured to the disc at diametrically opposite points bymeans of rivets 68, the connections to the respective coupling elements,therefore, being at right angles to each other. The elements arerecessed so as to provide clearance for flexing movement of the disc ineither direction.

The valve stem 64 is manually rotatable by means of a knob 59, having astem 'llll rotatably mounted'in a bearing element 1I fixed in a faceplate 12, which plate in turn is attachedi to the end wall of the frameIl. The stem of the knob has a gear 'i3 xed thereto, in mesh with a gear'i4 axially attached to the valve stem 64 through a sleeve l5. A coilspring 16 (Figure 5) under compression is disposed within a recess 'l1of the bearing member 1| and engages the knob 59 for frictionallyholding the gear in any set position by virtue of contact with thebearing member 1|. l

The valve stem 64 is supported at its actuated end by means of a bracket18 attached to the side wall lla of the frame. The sleeve 15 carries agraduated dial element 19, the graduations of which are visible througha sight opening 3|] in the face plate l2 and are movable in relation toa pointer 8|, formed in the margin of the sight opening. The graduationsindicate periods of exposure or, in other words, the elapsed time of*the bucky grid travel.

The sleeve element l5 and, therefore, the sleeve stem which is axiallydisposed within it, are additionally supported and held in axialalignment by means of a centering element 82, disposed within the boreof the sleeve and'xed to the face plate by means of a screw 83. Themanual adjustment movements of the knob 69 are conveyed to the valvestern from the sleeve i5 to a collar 84 which is fixed to the valvestem.

Because of the automatic movement of the valve stem imparted through thecushioning means hereinafter described, it is essential that there beclearance between the sleeve l5 and the collar S4. For this reason, atooth extension 35 of the sleeve 'i5 is adapted to engage with a toothextension of the collar 84. The rotative clearance between these teeth85, 85, is sufficient to permit the automatic bu'cky actuated closing ofthe valve and the cushioning action Without altering the setting of themanually operable knob 69.

'Ihe valve 46 is automatically moved to a closed position for bringingthe bucky grid to a cushioned or evenly decelerated stop by means of acam 8l carried by the bucky grid, being attached to an arm I3 thereof.This cam provides a curved surface adapted to engage a pin 88 of acollar 89 secured to the valve stem. A coil spring 9i) is fixed to thevalve stem having one terminal attached to the nearest coupling element,and the other terminal attached to the frame through the bracket 'i8 atits other end. This spring 90 is disposed about the valve stem and is awinding spring holding the valve in its manually set positions andreturning it to those positions when the cam element ill? is moved awayfrom its cooperating cam, namely the collar 89 and pin 88 on the valvestem.

Assuming that the guide and the control mechanism have been set orcocked as shown in Figure 1, that is, drawn into starting positionthrough manual operation of the knob i9, the operation is as follows:The operator determines the timing of the picture and sets dial 19 tothe appropriate position with respect to the pointer 8i. Although thewinding spring places a constant force on the valve stem, the dial willremain in set position due to the frictional engagement of gear 13 withthe bearing element 7l. The bucky grid is then tripped by way of thetrigger control through the ring 2l. The bucky grid then moves across ata speed determined by the position of the valve and the rate at whichthe oil can flow through the bypass. As it reaches the end of itstravel, the cam element on the valve stem, namely, collar 89 and pin 88,will be engaged by the cam 8l, whereupon the valve stem will be rotatedin valve closing direction. The closing of the valve is relativelygradual due to the flat curvature of the cam, and stopping will occurbefore, or at the precise moment at which, the buffers 9| engage the endwall of the frame, thereby, preventing shock or vibration resulting fromimpact. When the bucky grid is moved back in a resetting operation, therotative clearance between the collar 84 and the sleeves 15 permitsvalve return to set position as determined by the position of the knob6l, this return being entirely independent of the manual valve settingmeans. When the bucky grid is again cocked, the movable cam element onthe valve stem will return to its normal position under the action ofthe coil spring SQ, and the parts 'l5 and 8 4 will be in rotativecontact for` timing change through the knob 61 if desired VIn the formoi the invention shown in Figures 8 to 12, auxiliary valve |00 isprovided. The bucky grid` speed control valve is not automatically movedinthe preceding form. The control valve in this form is the same as thevalve found in latent No. 1,945,499, with the exception of the manuallyactuating mechanism thereof described in the preceding form. In otherwords, in the second form of the invention (Figures 8 to 12 inclusive)the manually set valve is not automatically moved during the bucky gridstroke. The bucky grid speed control valve 46 and the setting meanstherefor are the same as in the preceding form except that the automaticbucky grid actuated means is omitted.

The auxiliary Valve |00 is in the form of a segmental plate lyingagainst the inner side of the cylinder head 33 and mounted on a rod |0|,oiset from the axis of the cylinder. The valve plate includes a circularnotch |02 in its edge, registering with the port |03 connecting thecylinder to the bypass 43 through the passage 42. The valve rod 20| hasits outer end rotatively mounted in a bearing plate |04 extending fromone of the brackets 5 fixed to the frame ||a. The rod is suitably packedat its entry into the cylinder head 33 in the same manner in which thevalve rod or the main control rod is packed.

The rod |0| carries two cam elements |05 and |06 respectively,consisting in each case of sleeves, adjustably fixed on the rod by meansof screws |01 and radially extended pins |08. A cam |09 is fixed to theside of the bucky grid by means of a bracket H0. The cam |09 consists ofa plate including cam surfaces and ||2 respectively. The cam surfaces,of course, are angularly related to the path of movement of the buckygrid or the axis of the rod |0|, and are adapted to engage the camelements |05 and |06 respectively. Cam surfaces and ||2 are virtuallyparallel. The surface engages the pin of cam element |05 for rotatingthe valve |00 to partially closed position in the nal phase of buckygrid movement for the decelerating action previously described. Theclosing movement of the valve |00 is limited to the partially closedposition as shown in Figure 12 by contact with the wall of cylinder 3|as shown at I3. The open position of the valve is determined in the samemanner as shown in Figure 11, the Contact point being indicated at I4.The rearward surface 2 engages the cam element |06 (which has been movedinto the path of this surface) upon the return or setting movement ofthe bucky grid. This latter action returns the valve to normal, fullyopened position, as shown in Figure 11.

Having described my invention, I claim:

1. A mechanism for controlling the speed of motion of a bucky grid anddecelerating the same, comprising, a cylinder, a piston in said cylinderconnected to said bucky grid, a valve in said piston opened by returnmovement of the bucky grid, said cylinder including a ley-passageconnecting the ends thereof, said cylinder and by-passage substantiallycompletely lled with liquid, a valve in the liquid circuit formed bysaid cylinder and said by-passage, cooperating elements on the buckygrid and in connection with the valvev operative in the nal phase ofbucky grid movement for gradually closing the valve and graduallydecelerating the bucky grid.

2. A mechanism for controlling the speed of motion of a bucky grid andfor decelerating the same, comprising, a cylinder, a piston in saidcylinder connected to said bucky grid, said cylinder including any-.passage connecting the ends thereof, said cylinder and by-passagebeing substantially completely lled with liquid, a control valve in saidby-passage, means for setting said control valve for a timed movement ofsaid bucky grid, and a bucky grid actuated decelerating valve in theliquid circuit of said cylinder and by-pas- Sage..

3. A mechanism for controlling the speed of motion 0f a bucky grid anddecelerating the same, comprising, a cylinder, a piston in said cylinderconnected to said bucky grid, said cylinder including a ily-passageconnecting the ends thereconnection with the valve operative in the nalphase of bucky grid movement for gradually closing the Valve andgradually deoelerating the bucky grid.

4;. A mechanism for controlling the speed of motion of a bucky grid,comprising, a cylinder, a piston in said cylinder connected to saidbucky grid, a valve in said piston opened by return movement of thebucky grid. a bi1-passage connecting the ends of said cylinder, saidcylinder and by-passage substantially completely lilled with liquid, adecelerating valve in said by-passage, a earn element on the bucky gridactuating the valve toward the conclusion of the bucky grid motion forautomatically gradually closing the valve as the bucky grid reaches theend of its prescribed movement. and setting means for regulating the iowof liquid through the by-pas- Sage.

5.. A mechanism for controlling the speed of motion of a bucky grid andfor decelerating the same. comprising. a cylinder, a piston in saidcylinder Connected te .said bucky grid. said cylinder including aby-passage connecting the ends thereof, said cylinder and by-passagebeing substantially completely iled with liquid, a valve in saidley-passage, a manually operated valve control knob connected to saidvalve including graduations for showing the degree of by-passagepermitted bysaid valve as determined by its position,

stops for said bucky grid and an element on the bucky grid actuatingsaid valve for gradually closing the same toward the end of bucky gridmovement whereby the-bucky grid is substantially stopped when itlengages the stops.

6. A mechanism for controlling the speed of motion 0f and. deceleratinsa bucky grid comprising, a liquid filled cylinder, a piston insaidcylinder connected to. said bucky grid, valve means for controllingthe displacement o f the liquid from one end of the cylinderto theother,l a control knob connected to said valve means, and means on saidbucky grid engageable with the valve means in the final phase of buckygrid movement for operating the valve and therefore graduallyde-celerating the bucky grid.

7. Apparatus for controlling the speed of motion of a bucky grid,comprising, a cylinder, a pistcn in the cylinder connected to the buckygrid, a` conduit connecting the ends of the cylinder for permittingmovement of liquid completely lling the cylinder and conduit, from oneend of the cylinder to the other, a valve in said conduit including avalve stem, a manually operated knob connected to the valve, a frictiondevice associated with the knob for holding the knob against accidentaldisplacement, a Winding spring exerting a rotative pressure on the valveinsuflicient to displace the knob, a valve rotating device between thebucky grid and the valve for closing the valve during the last phase ofmovement of the bucky grid, and coupling elements between the knob andthe valve stem permitting independent movement of the valve whenactuated by said device, whereupon the winding spring returns the valveto the knob determined position when the bucky grid is reset.

8. A mechanism for controlling the speed of motion of a bucky grid,comprising, a cylinder, a piston in said cylinder connected to saidbucky grid, a valve in said piston opened by return movement of thebucky grid, a by-passage connecting the ends of said cylinder, saidcylinder and by-passage substantially completely iilled with liquid, avalve in said by-passage, a manual adjustment device connected to thevalve for Varying its position, and a cam element on the bucky gridactuating the valve toward the conclusion of the bucky grid motion forautomatically gradually closing the valve as the bucky grid reaches theend of its prescribed movement.

9. A mechanism for controlling the speed of motion of and decelerating abucky grid comprising, a liquid iilled cylinder, a piston in saidcylinder connected to said bucky grid, by-passage means connecting therespective ends of the cylinder, valve means for controlling thedisplacement of the liquid from one end of the cylinder to the other,and means on said bucky grid engageable with the valve means in thefinal phase of bucky grid movement for operating the valve and thereforegradually decelerating the bucky grid.

10. Apparatus for controlling the speed of motion of a bucky grid,comprising, a cylinder, a piston in the cylinder connected to the buckygrid, a conduit connecting the ends of the cylinder for permittingmovement of liquid completely lling the cylinder and conduit, from oneend of the cylinder to the other, a valve in said conduit including avalve stem, a manually operated knob connected to the valve stemincluding a graduated dial for indicating the speed of bucky grid travelas permitted by the valve, a friction device associated with the knobfor holding the knob against accidental displacement, a winding springexerting a rotative pressure on the valve insufficient to displace theknob, a cam element on the valve stem, a cam element on the bucky gridadapted to engage the cam element of the valve stem for graduallyclosing the valve during the last phase of movement of the bucky grid,and coupling elements between the knob and the valve stem permittingindependent movement of the valve when actuated by the cam, whereuponthe winding spring returns the valve to the knob controlled positionwhen the cams are disengaged.

11. A mechanism for controlling the speed of motion of a bucky grid andfor decelerating the same, comprising, a cylinder, a piston in saidcylinder connected to said bucky grid, said cylinder including aby-passage connecting the ends thereof, said cylinder and by-passage`being substantially completely filled with liquid, a valve in saidby-passage, a manually operated valve control knob connected to saidvalve including graduations for showing the degree of by-passagepermitted by said valve as determined by its position, stops for saidbucky grid, a decelerating valve in the liquid circuit formed by saidcylinder and luy-passage and an element on the bucky grid actuating saiddecelerating valve for gradually closing the same at the end of buckygrid movement whereby the bucky grid is substantially stopped when itengages the stops.

EDWIN S. FLARSI-IEIM.

